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FEATURES
• LOW BIAS CURRENT, LOW NOISE — FET Input
• FULLY PROTECTED INPUT — Up to ��150V
• WIDE SUPPLY RANGE — ±15V to ±150V
APPLICATIONS
• HIGH VOLTAGE INSTRUMENTATION
• ELECTROSTATIC TRANSDUCERS & DEFLECTION
• PROGRAMMABLE POWER SUPPLIES UP TO 290V
• ANALOG SIMULATORS
8-PIN TO-3
PACKAGE STYLE CE
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DESCRIPTION
The PA83 is a high voltage operational amplifier designed
for output voltage swings up to ±145V with a dual (±) supply or
290V with a single supply. Its input stage is protected against
transient and steady state overvoltages up to and including
the supply rails. High accuracy is achieved with a cascode
input circuit configuration. All internal biasing is referenced
to a zener diode fed by a FET constant current source. As
a result, the PA83 features an unprecedented supply range
and excellent supply rejection. The output stage is biased in
the class A/B mode for linear operation. Internal phase com-
pensation assures stability at all gain settings without need
for external components. Fixed current limits protect these
amplifiers against shorts to common at supply voltages up to
120V. For operation into inductive loads, two external flyback
pulse protection diodes are recommended. However, a heatsink
may be necessary to maintain the proper case temperature
under normal operating conditions.
This hybrid circuit utilizes beryllia (BeO) substrates, thick
(cermet) film resistors, ceramic capacitors and silicon semicon-
ductor chips to maximize reliability, minimize size and give top
performance. Ultrasonically bonded aluminum wires provide
reliable interconnections at all operating temperatures. The
8-pin TO-3 package is hermetically sealed and electrically iso-
lated. The use of compressible thermal isolation washers and/or
improper mounting torque voids product warranty. Please see
Application Note 1 “General Operating Considerations”.
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TYPICAL APPLICATION
While piezo electric transducers present a complex imped-
ance, they are often primarily capacitive at useful frequen-
cies. Due to this capacitance, the speed limitation for a given
transducer/amplifier combination may well stem from limited
current drive rather than power bandwidth restrictions. With
its drive capability of 75mA, the PA83 can drive transducers
having up to 2nF of capacitance at 40kHz at maximum output
voltage. In the event the transducer may be subject to shock
or vibration, flyback diodes, voltage clamps or other protection
networks must be added to protect the amplifier from high
voltages which may be generated.
EQUIVALENT SCHEMATIC
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APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
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CIRRUS [ CIRRUS LOGIC ]
